| 翻訳と辞書 |
| Réaumur scale ： ウィキペディア英語版 |
Réaumur scale
__NOTOC__
The Réaumur scale (°Ré, °Re, °R), also known as the "octogesimal division",〔''Division octogesimale'' in French.〕 is a temperature scale in which the freezing and boiling points of water are set to 0 and 80 degrees respectively. The scale is named after René Antoine Ferchault de Réaumur, who first proposed something similar in 1730.
== Change in scale ==
Réaumur’s thermometer contained diluted alcohol (ethanol) and was constructed on the principle of taking the freezing point of water as 0°, and graduating the tube into degrees, each of which was one-thousandth of the volume contained by the bulb and tube up to the zero mark. He suggested that the concentration of alcohol employed be such that it began boiling at 80 °Ré — that is, when it had expanded in volume by 8%. He chose alcohol instead of mercury because it expands more visibly, but this posed problems: his original thermometers were very bulky, and the low boiling point of alcohol made them unsuitable for many applications. Instrument-makers generally chose different liquids, and then used 80 °Ré to signify the boiling point of water, causing much confusion. In 1772 Jean-André Deluc studied the several substances then used in thermometers in the light of new theories of heat and came to the conclusion that mercurial thermometers were the best for practical use; for example, if two equal amounts of water at ''x'' and ''y'' degrees were mixed, the temperature of the result was then the average of ''x'' and ''y'' degrees, and this relationship only held reliably when mercury was used. From the late 18th century mercury was used almost without exception. These thermometers, the stems of which are graduated into eighty equal parts between the freezing and boiling points of water, are not Réaumur's original thermometers in anything but name.〔Herbert Dingle. ''The scientific adventure: essays in the history and philosophy of science.'' Sir Isaac Pitman and Sons, London, 1952. Page 131.〕
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Réaumur scale」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|